I don't know if I would trust something like that to hold my mag. Not because I don't trust magpul's, but because that is mainly for SMG mags that stick out of the magwell. And with the M9, the only area for that to hold the mag from would be from the baseplate.

What about on the 48rd mags? A buddy is looking to get rid of his 4 M93R mags, I was thinking of getting one. These just looked cool I wish I could use the rifle mag assists of my flash mags, but I can't wind them with them on. Anyone who has these knows what huge pain in the a** they can be to get on.

Yup. I have Magpuls for my SR10 mags. Its unfortunate that we won't really be able to use these for the LM4 mags either because we have to load the gas from the bottom. THis means no ranger plates or magpuls!
I could see it working on the M93 mags as long as its the proper dimensions and not too wide. I don't like the way extended mags look in the M9 for some reason though